Method for dynamically guiding a dental oral and maxillofacial prosthesis using a 3d dataset

ABSTRACT

An approach is disclosed that involves creating an implant-supported prosthesis that is dynamically guided into position using an image-guided navigation system into position in a patient’s mouth without the use of a surgical guide.

RELATED APPLICATIONS

This application is a divisional of and claims priority to U.S. Pat.Application 16/582,666, filed Sep. 25, 2019, which is related to andclaims priority from United States Provisional Application 62/737,539,filed Sep. 27, 2018. The disclosures of both applications areincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

An improved dental/maxillofacial implant method and apparatus isdisclosed, and, more particularly a dental and maxillofacial prosthesisthat is guided into position to fit on the patient’s jaw andmaxillofacial structures without the use of a surgical guide. The methodinvolves the use of an image-guided navigation system to determine theposition of the prosthesis on the patient’s jaw and maxillofacial regionand placing the prosthesis accurately without the use of a physicalsurgical guide.

BACKGROUND

The use of surgical navigation in the head and neck has made significantadvancements in the past few years. Presently, systems are used inotolaryngology, neurosurgery and oral and maxillofacial surgery for avariety of surgical procedures. Some examples of the existingtechnologies are disclosed in US Pat. Nos. 9,943,374, 9,402,691,9,844,324, the disclosures of which are each incorporated herein byreference in its entireties.

Recent advances allow dentists, oral and maxillofacial surgeons andmaxillofacial prosthodontists to place dental implants accuratelywithout the use of physical surgical guides using these image guidednavigation systems. Once the implants are placed, relating aprefabricated dental and maxillofacial prosthesis to the implants hasremained a challenge.

Physical guides are presently used to orient a pre-surgically fabricatedprosthesis to the implants. The problem with these physical guides isthat they require large incisions and complex fabrication techniquesoften utilizing stacked, indexed guides and frame sets. If the guidesare not accurately aligned related to the bone they often do not fit thepatient properly. In regions outside the oral cavity they are oftenimpossible to place into the maxillofacial defect.

A need exists for an improved system for accurately and easily placing aprosthesis to an implant with minimal trauma to the patient.

SUMMARY OF THE INVENTION

A method for determining final locations of a set of implants relativeto a three-dimensional dataset is disclosed in one embodiment. Themethod includes the steps of (i) providing a three-dimensional datasetincluding a planned location of the set of implants; a location of a setof implants surgically to be placed in a patient; and an actual locationof a patient as provided by a patient tracker attached to the patient,wherein a transform relates the patient tracker to the three-dimensionaldataset; (ii) using a tracking system to measure the location of the setof implants simultaneously with the patient tracker; and (iii)communicating a final location of the set of implants relative to thethree-dimensional dataset.

Preferably the step of providing the three-dimensional dataset includesobtaining the three-dimensional dataset from a three-dimensionalradiograph.

The three-dimensional radiograph may be a cone beam computed tomogram.

The three-dimensional radiograph may be an intra-oral scan.

The step of providing the three-dimensional dataset preferably includesaccessing digital files representing the three-dimensional dataset by anavigation system.

In an embodiment the tracking system includes registering digitaldatasets representative of the planned location of the set of implants,the location of the set of implants, and the actual location of thepatient are then registered to each other within a common coordinatesystem.

Optionally the steps of registering the planned location of the set ofimplants, the location of the set of implants, and the actual locationof the patient includes spatially aligning common features of eachimagining modality using rigid-body transformation.

In an embodiment, the method may include determining the plannedlocation of the set of implants.

Preferably the step of determining the planned location of the set ofimplants includes outlining anatomical features of the patient.

It is contemplated that the step of determining the planned location ofthe set of implants may include determining a desired position and adesired angulation of the set of implants.

Preferably the step of determining the planned location of the set ofimplants includes determining a hole size of for receiving the set ofimplants.

In an embodiment that step of determining the hole size is calculated byusing a formula defined as Do + 2 (Et + H x tan(Ea)).

In an embodiment, a method of dynamically tracking an implant procedureis discloses. The method includes the steps of (i) receiving by atracking system a first digital data set representative of athree-dimensional radiograph obtained of a patient; (ii) determining aplanned implant location for a dental implant based on the first digitaldataset; (iii) attaching an implant tracking fiducial to the dentalimplant; (iv) attaching a patient tracking fiducial to the patient; (v)positioning the tracking system relative to the patient; (vi) using thetracking system to measure a location of the implant tracking fiducialsimultaneously with a location of the patient tracking fiducial; and(vii) communicating the planned implant location relative to thelocation of the implant tracking fiducial.

In an embodiment the method may include registering the implant trackingfiducial to the tracking system.

It is contemplated that the implant tracking fiducial may include aplate with a printed pattern.

The method may include the step of forming holes in the dental implant.

In an embodiment the step of forming holes in the dental implantincludes determining a hole size by using a formula defined as Do + 2(Et + H x tan(Ea)).

The method may optionally include a further step of projecting imagecoordinates of the planned implant location into the tracking system.

Preferably the method includes the step of using the planned implantlocation to cue the tracking system where to look for the implanttracking fiducial.

The implant tracking fiducial may be in a shape of a protruding portionof the dental implant.

The foregoing and other features of the invention and advantages of thepresent invention will become more apparent in light of the followingdetailed description of the preferred embodiments, as illustrated in theaccompanying figures. As will be realized, the invention is capable ofmodifications in various respects, all without departing from theinvention. Accordingly, the drawings and the description are to beregarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, the drawings show a formof the invention that is presently preferred. However, it should beunderstood that the invention is not limited to the precise arrangementand instrumentalities show in the drawings. It should also be understoodthat the invention is not limited to the anatomic location illustratedbut may be used in or on any maxillofacial structure suitable for theuse of dental implants.

FIG. 1 is a cross-sectional view of a dynamically guided supportstructure according to the present invention shown in the stages ofbeing mounted on a bone.

FIG. 2 is a perspective view of a portion of a patient’s jawillustrating one embodiment of an alignment support system for locatinga prosthesis on multiple implants with abutments for the implantslocated on the implants before attachment.

FIG. 3 is a perspective view of a portion of a patient’s jawillustrating one embodiment of the alignment support system for FIG. 2as it provides guidance on placement of the prosthesis.

FIG. 4 is a perspective view of a portion of a patient’s jawillustrating the prosthesis of FIG. 3 with the abutments attached to theprosthesis.

FIG. 5 is a perspective view of a portion of a patient’s jawillustrating the prosthesis of FIG. 4 with the alignment support systemremoved.

FIG. 6 is a perspective view of a portion of a patient’s jawillustrating one embodiment of an alignment support system for locatinga prosthesis in place on the jaw with the alignment support systemattached.

FIG. 7 is a schematic illustration of the calculations used to determinethe size of the prosthetic holes as they relate to the dynamicallyguided navigation system.

DETAILS DESCRIPTION OF THE INVENTION

The present invention is directed to a system and method to allow adentist to plan an implant position prior to surgery using a dynamicnavigation system, plan the prosthesis related to the implant plan andthen accurately relate the prosthesis to the patient’s anatomy and thenewly placed implants without the use of a physical surgical guide.Minimal incisions are used as no guides are necessary. In a preferredembodiment, the prosthesis includes an alignment support structure forassisting with the proper positioning of the prosthesis with respect tothe patient anatomy during fitting, and one or more implant fixationsystems for final fixation of the prosthesis to the anatomy, each ofwhich consists of a fixation feature, which in the preferred embodimentis a hole in the prosthesis, an abutment that will be rigidly attachedto the fixation feature, and an implant that will be drilled into thepatient’s bone and that will be removably mated to the abutment.

The system involves first obtaining a pre-surgical data set that isacquired from the patient through an image scanning. The pre-surgicaldigital data set is to be used by the dynamic image navigation systemfor planning the implant and then the prosthesis. This digital data setmay be obtained using any conventional means, and may include a threedimensional radiograph; a computed tomogram or cone beam computedtomogram; an intraoral digital scan; digital scans of models; and/ordigital photographs, either 2D or 3D.

To obtain the digital data set, a three dimensional radiograph is taken,preferably a cone beam computed tomogram (CBCT) taken with or withoutradiographic markers or fiducials attached rigidly to the patient’sskeleton/bone structure in the area of the scan, either with screws or aremovable device. If desired, a scanning appliance withmarkers/fiducials may be attached to the patient’s mouth at the time ofthe radiograph to assist with the surgical planning. One type ofappliance is disclosed in U.S. Pat. 9,402,691 the disclosure of which isincorporated herein by reference in its entirety. This appliance may becustom-made with fiducials or, alternatively, could be the patient’sdenture or a dental appliance that has fiducials attached. The CBCT maybe taken with the patient’s teeth touching, in occlusion, or with theteeth separated. If the patient has no teeth, the dentures or scanningappliance may or may not be touching or in occlusion. The radiograph ispreferably stored in a digital imaging and communication (DICOM) format.

It is also contemplated that intra-oral optical scans may, optionally,be used in the surgical planning. Intra-oral scans are typically storedin a surface format consisting of a triangulated irregular network (TIN)of 3D points representing one or more surfaces of a patients anatomy.Intra-oral scans are typically registered via matching surface contourinformation with a surface extracted from the 3D radiograph. Intra-oraloptical scans provide additional information about soft-tissueboundaries and are less susceptible to image artifacts that can lead toambiguity in determining hard-tissue structure, so can assist inplanning around the anatomical features. In addition, the inventioncontemplates the use of laser scans of physical models, which may or maynot be used. These models may, for example be wax-ups of the desiredrestorative result, the patient’s existing denture, or a provisionalprosthesis.

Three- or two- dimensional photographs in digital format may also beused.

The digital files are brought into (accessed by) the image navigationsystem planning software. For example, the digital data files may beimported into the navigation system, or the software can access thedigital data files from a stored location (which can be local orremote). The digital datasets are then registered to one another tobring them into a common coordinate system. The registration consists ofspatially aligning common features of each imaging modality using arigid-body transformation in order to minimize the spatial disparitybetween the common features once aligned. In the case of registeringintra-oral scans to CBCT scans, this typically involves first extractingan isosurface or other surface estimate from the CBCT scan by analyzinghigh-gradient regions of the CBCT scan data, then determining analignment between the surface estimate and the intra-oral scan data. 2Dor 3D photos can also be registered to the 3D dataset by determining therelationship between coordinate system of the camera that produced themand the CBCT scan, which is done by determining correspondences betweenfeature points in both modalities and using either a perspectiveN-points algorithm for 2D images, or an absolute orientation algorithmfor 3D images. Alternative registration algorithms can be contemplatedwhich similarly minimize the matching disparity between modalities.

Using the image navigation system planning software, the relevantanatomy is outlined and mapped to determine location of pertinentanatomy. The arch form, also referred to as the panoramic curve, can bemanually marked by the doctor by marking control points at key locations(e.g., known tooth locations) along the patient’s arch, and thenconnected using a spline curve. These splines can also be automaticallydetected based upon an algorithmic analysis of the CBCT data. Nervecanals can also be manually marked by the surgeon by defining controlpoints in cross-sectional slices of the CBCT scan. The hard tissue (boneand teeth) is automatically segmented within the CBCT scan by analyzingthe HU values in the CBCT scan to determine interfaces between hardtissue and soft tissue or air. This can also be performed with doctor inthe loop, where the segmentation can be seeded or further refined byhuman interaction. Teeth and sinus can be further segmented based onanatomical atlas analysis and/or shape-prior analysis. Depending on thesurgical location and procedure, other items of the patient’s anatomymay be segmented either in a doctor-assisted manner or in afully-automated way.

The doctor uses the image navigation system planning software to planwhich implants to use and plan the locations for them, as well as theamount of bone reduction needed during the surgery. The level of theimplant platforms, where the prosthesis will ultimately engage with theimplants, is determined by considering the height of the desiredprosthesis and the vertical engagement overlap between the prosthesisand the implants. The bone reduction is then planned to allow properspacing between the bone and the desired prosthesis.

Next, the prosthesis is planned, with space for soft tissue under theprosthesis. Planning consists both of determining the position andangulation of the prosthesis, as well as its shape. Position andangulation can be manipulated by the doctor in the planning software bydragging the prosthesis in cross-sectional slices in the planningsoftware. Shape can be defined based upon a scan of a wax-up, by theresults of a design from a 3D modeling software, or by adjusting,stretching, and merging 3D models of virtual teeth with a portion of thebone anatomy extracted from the CBCT scan or intra-oral scan. The amountof vertical space for soft tissue must be noted. The size of the holesin the prosthesis will be calculated based upon the accuracy of thedynamic image navigation system. The following deviations areconsidered: Angular deviation; Horizontal coronal deviation; Horizontalapical deviation; and Vertical deviation.

The hole size is determined by using the following mathematical formula(Formula 1) incorporating the accuracy of the dynamic image navigationsystem, the vertical position of the planned prosthesis, the entry andexit of the implant components. See. FIG. 7 .

$\begin{matrix}{Dn = Do + 2\left( {Et + H\mspace{6mu} x\mspace{6mu}\tan\left( {Ea} \right)} \right)} & \text{­­­Formula 1}\end{matrix}$

-   Where Dn = New over-drilled diameter-   Do = Original diameter-   Et = Translational component of error-   H = Distance from implant platform to prosthesis-   Ea =Angular component of error

The system then calculates the attributes of the dynamically guidedprosthesis to aid in manufacturing. Digital dynamically-guidedprosthetic alignment support structure is planned. In a preferredembodiment, the alignment support structure is comprised of multiplealignment support systems. Referring to FIGS. 1 - 6 , each supportsystem 10 consists of a central pin 20 and two alignment features 22,which assist in aligning the prosthetic P in its proper orientation whenplaced in the patient’s mouth. In a preferred embodiment, three or moreof these support systems are used, and are spread throughout locationson the arch, for example one support system in the anterior and onesupport system posterior on each side of the arch. It is contemplatedthat the central pin(s) 20 will be located on the prosthesis P so as tocontact areas on the bone B where implants 30 will not be placed. Theymay be placed mesial or distal to any planned implant below the plannedprosthesis. Fewer support systems can be used if sufficient stabilitycan be achieved. The support structure 10 may also consist of otherarrangements and combinations of central pins and alignment features, ormay consist of only central pins or alignment features. The central pin20 is configured to project into the bone B, below the level of theplanned implant platform, or the level of bone reduction, preferably bya minimum of 3 mm. The central pin’s full length below the plannedprosthesis is, therefore, calculated to be the length for accommodatingsoft tissue (if any) plus the projected length into the bone B below thelevel of the bone reduction or the platform height. A planned hole 24 isdrilled into the patient’s bone B (osteotomy) for the central pin 20 andis preferably larger than the pin, by a margin that is determined by theaccuracy of the navigation system. This is calculated using the lateraland vertical margins of error of the navigation system.

On the buccal and lingual, or palatal and labial sides of the centralpin 20, two alignment features 22 are provided. The alignment featurespreferably engage the bone surface B below the level of the plannedimplant platforms. The shape of these bone supports may vary but theypreferably complement the shape of “virgin” bone to engage with it, andare sufficiently rigid to prevent distortion. Although the alignmentfeatures 22 are depicted as curved “arms” in the figures, it should bereadily apparent that the alignment features could be tapered orstraight “arms”. The alignment features 22 are designed to providetemporary alignment and lateral support for the prosthesis Importantanatomic structures should be avoided. Thus, the support system 10 foreach prosthesis should be designed to accommodate these anatomicstructures. In the preferred embodiment, the planned prosthesis ismanufactured with the alignment support system incorporated directlyinto the prosthesis, and made out of the same material as theprosthetic, with the intention that the alignment features and centralpins will be cut off once the surgery is complete.

At the time of surgery, small incisions are made to expose the sites ofthe implants and reduce the bone. The implant positions are navigatedusing the dynamic image-guided navigation system and the surgical plan,and the osteotomies for the central pins of the alignment support systemare navigated and holes drilled into the bone. The implants 30 are thenplaced in the bone. The implants and implant abutment 34 form atwo-piece attachment mechanism that will provide the long-termattachment between the bone and the prosthetic once the alignmentsupport system is removed. Implants and abutments are well known and,therefore, no detailed discussion is necessary. The implants 30 willremain screwed into and engage the bone, and typically have a femaleinternal mounting thread. The abutments 34 are typically designed to beremovably screwed into the implant 30 via a screw (not shown) throughthe abutment which engages with the internal implant threads. There aremany other implant/abutment systems and the attachment mechanism varieswidely. Once the implant 30 has been placed, the prefabricated implantabutments 32 are then temporarily attached to the implants 30. FIG. 2 .The abutments 32 will ultimately be glued into holes in the prosthetic,and will be the mechanism by which the prosthetic is attached to theimplants 30, but attaching the abutment 32 to the implant 30 at thispoint ensures that the abutments 32 will be properly aligned to theirrespective implants 30 once the abutments 32 have been glued in place inthe prosthetic P. The prefabricated prosthesis P is placed over theabutments 32 and the central pin(s) 20 are engaged in their appropriatebone holes 24 (osteotomies). FIG. 3 . The buccal and lingual, palataland labial alignment features 22 of the alignment support system arethen pushed into contact with the bone B, which helps to set the finalvertical position with respect to the bone. The patient is placed intheir final bite, occlusion, so that the patient’s opposing dentitioncomes in contact with and aligns with complementary occlusal surface ofthe prosthesis. This bite forces the prosthesis to move into a positionwhere the occlusion happens at many points to provide the best level ofcomfort to the patient. Once in occlusion, a dental adhesive material isinjected into the holes in the prosthesis to affix the prosthesis to theabutments in order to fix the prosthesis in its final position.

Once the adhesive material has set, the abutments are detached from theimplants. FIG. 4 . The prosthesis, and its now-fixed abutments areremoved from the mouth and the alignment support systems are removedfrom the prosthesis by cutting using dental instruments. FIG. 5 . Theprosthesis is then finished and put in place. FIG. 6 .

Numerous alternate embodiments exist.

In one such embodiment, the prosthesis can be manufactured prior to thesurgery without the prosthetic holes. The prosthetic holes can then bemilled in the doctor’s office before or after placing the implants. Theholes can accurately be drilled by using the same tracking system asused for guidance of the osteotomy, by first attaching a trackingfiducial to the prosthesis and then registering the prosthesis to thetracking system, which can be performed e.g., by using a keyedconnection to the tracking fiducial, or by touching or scanning overportions of the prosthesis with a tracked surgical instrument.Alternately, the prosthetic holes could be made using an in-officemilling machine, which could be simplified by incorporating mechanicalregistration features to reproducibly place the prosthesis into a knownalignment within the milling machine prior to milling. In-officedrilling of the prosthesis holes has the advantage that the implant planmay be changed on the day of surgery if surgical conditions find thatthe initially planned implant locations are not clinically acceptable.

In a further embodiment, the shapes and locations of the prostheticholes can be determined by measuring the final implant locations ratherthan by using the planned implant locations. In the measurement process,the surgeon would first attach an implant fiducial onto each of theplaced implants, using a keyed attachment mechanism that is designed tomate with the implant’s attachment system in the same way that implantabutments attach to implants. The surgeon then positions the trackingsystem relative to the patient such that each tracking fiducial can bemeasured simultaneously with, and relative to the patient trackingfiducial. It should be noted that each implant tracking fiducial doesnot necessarily need to be measured simultaneously with each other, onlywith the patient tracking fiducial. This measurement, in combinationwith the patient tracker registration, allows for determining the finallocation of each implant relative to the original DICOM coordinatesystem that formed the basis of the prosthesis design. An example ofsuch a patient tracking system and patient tracking fiducial isdescribed in more detail in U.S. Pat. 9,943,374. The implant fiducial oneach implant could be a small plate with a printed pattern of corners ordots, a constellation of 3 or more reflective spheres, which would betracked using triangulation of feature points. Alternately, the implantfiducial could be a unique, asymmetric shape, such as a scan body, whoseshape could be reconstructed by the stereo tracking system and matchedto the fiducial’s geometric model using, for example, the iteratedclosest points (ICP) algorithm. In a further embodiment, the trackingsystem could track the shape of the protruding portion of the implantitself, rather than using a separate implant fiducial. The computationalcomplexity of measuring the tracking fiducial locations can be reducedby using the planned implant locations to cue the system where to lookfor the tracking fiducials. Once the patient tracking fiducial has beenidentified, the 3D locations of the planned implant locations are knownand can be projected into the tracking system’s image coordinates,allowing a search to take place only in the neighborhood of thoselocations in the images, or if using ICP, allows the iteration to beginwith the model in its planned location and to converge to its finalmeasured location. One advantage of measuring the final implant locationis that this removes the component of error associated with thesurgeon’s skill at following their plan, which leaves only the trackingsystem’s intrinsic error, which is generally smaller and, therefore,allows the prosthetic holes to be oversized by a smaller margin. Anintra-oral scanner can also be used for measuring final implantlocations instead of a dynamic navigation system. The scanner willreconstruct the surface of the dental anatomy, along with the surfacesof scan bodies attached to the implants. Identifying the scan bodies inthe intra-oral scan and registering these surfaces to the anatomicalsurfaces in the CBCT scan allows the final implant locations to becomputed with respect to the DICOM coordinate system.

In a further embodiment, the holes would not be present in theprefabricated prosthetic, so they could instead be determined at thetime of surgery. Once final implant locations are measured, the surgeoncould then drill new holes using the tracking system, or have the holesmilled. Similarly, the surgeon could enlarge existing prosthetic holesif the final implant positions shifted from their planned locations bymore than the tolerance of the holes allows, The process of measuringfinal implant locations and enlarging holes could be an optionalfollow-up step performed if the prosthetic is found to not seat properlydue to excessive implant placement error by the surgeon.

Variations of the alignment support system can be used. The central pinmay be omitted. Instead, implant abutment sleeves, which are typicallysmooth-walled plastic sleeves that attach to the top of the abutmentusing a retention screw, can be used for lateral alignment stabilitywhen setting occlusion. These abutment sleeves would mate withcomplementary features machined into the prosthesis. Alternately,different pins may be used, e.g., removable and reuseable pins could beused and could be made of titanium or other materials. The alignmentfeatures can also be made of different materials and attached into theprosthetic. The mating system for these alignment features could allowfor reusable alignment of varying sizes, which would allow the user tofine-tune the fit by adjusting to shorter or longer supports or supportswith different curvatures if, for example, the prosthesis cannot bebrought into occlusion as planned.

In a further embodiment, the alignment support system could be dynamic,rather than a mechanical alignment system. In this approach, theprosthesis can be brought into occlusion and temporarily affixed to theopposing dentition in occlusion. The jaw position could then bemanipulated until the prosthesis is in the desired position relative tothe surgical jaw. The tracking system would determine the position bymeasuring a tracking fiducial attached to the surgical jawsimultaneously with a tracking fiducial attached to the prosthesis, andwould provide feedback to assist in properly positioning the mandible tobring the prosthesis and the surgical jaw into proper (as-planned)alignment. Once in alignment, the prosthesis would be affixed to theabutments by injecting dental material into the holes, therebypreserving the desired alignment. This process could be assisted byusing materials to shim the prosthesis so it would remain more stablewhile the dental material cures in the holes.

Variations in the prosthesis can be foreseen. The prosthesis can bemachined from various materials, including ceramics such as Zirconia,plastics such as PEEK, PMMA, and composite materials. The prosthesiscould also be grown using 3D printing method as known to those skilledin the art. The prosthesis could include integrated metal supportstructures e.g., to support the alignment support pins or to support akeyed tracking fiducial, or could include machined fiducial touchfeatures that would allow the surgeon to touch the fiducial featureswith a tracked instrument in order to assist the surgeon in registeringthe alignment of the prosthesis to an attached tracking fiducial.

Variations in the dynamic guidance system can be used. Optical trackingsystems, based on multi-camera triangulation or monocular triangulation,time of flight, or wave-front technologies could be used, as well aselectromagnetic tracking, inertial sensing, ultrasonic or field effecttechnologies could be used. Likewise, robotic navigation systems can beused to assist in drilling the actual osteotomies and the holes in theprosthetic. This would have the benefit of reducing the component oferror due to the surgeon’s ability to follow the implant plan, whichwould result in the holes being oversized by a smaller margin.

While the present invention has been described for placing a fitteddental prosthesis within an oral cavity, the invention can also be usedto attach any implant supported maxillofacial prosthesis within or onany maxillofacial structure, for example, eye, nose, ear, maxilla,mandible, zygoma or frontal bone.

The system or systems described herein may be implemented on any form ofcomputer or computers and the algorithms and programs may be implementedas dedicated applications or in client-server architectures, including aweb-based architecture, and can include functional programs, codes, andcode segments. The computer system of the present invention may includea software program be stored on a computer and/or storage device (e.g.,mediums), and/or may be executed through a network. The computer stepsmay be implemented through program code or program modules stored on astorage medium.

For the purposes of promoting an understanding of the principles of theinvention, reference has been made to the preferred embodimentsillustrated in the drawings, and specific language has been used todescribe these embodiments. However, no limitation of the scope of theinvention is intended by this specific language, and the inventionshould be construed to encompass all embodiments that would normallyoccur to one of ordinary skill in the art.

The computer processes herein may be described in terms of variousprocessing steps. Such processing steps may be realized by any number ofhardware and/or software components that perform the specifiedfunctions. For example, the described embodiments may employ variousintegrated circuit components, e.g., memory elements, processingelements, logic elements, look-up tables, and the like, which may carryout a variety of functions under the control of one or moremicroprocessors or other control devices. Similarly, where the elementsof the described embodiments are implemented using software programmingor software elements the invention may be implemented with anyprogramming or scripting language such as C, C++, Java, assembler, orthe like, with the various algorithms being implemented with anycombination of data structures, objects, processes, routines or otherprogramming elements. Functional aspects may be implemented inalgorithms that execute on one or more processors. Furthermore, theembodiments of the invention could employ any number of conventionaltechniques for electronics configuration, signal processing and/orcontrol, data processing and the like. The words “mechanism” and“element” are used broadly and are not limited to mechanical or physicalembodiments, but can include software routines in conjunction withprocessors, etc.

The particular implementations shown and described herein areillustrative examples of the invention and are not intended to otherwiselimit the scope of the invention in any way. For the sake of brevity,conventional electronics, control systems, software development andother functional aspects of the systems (and components of theindividual operating components of the systems) may not be described indetail.

Finally, the steps of all methods described herein are performable inany suitable order unless otherwise indicated herein or otherwiseclearly contradicted by context. The use of any and all examples, orexemplary language (e.g., “such as”) provided herein, is intended merelyto better illuminate the invention and does not pose a limitation on thescope of the invention unless otherwise claimed. Numerous modificationsand adaptations will be readily apparent to those skilled in this artwithout departing from the spirit and scope of the invention.

1. A method for determining final locations of a set of implantsrelative to a three-dimensional dataset, the method comprising the stepsof: a. providing a three-dimensional dataset including a plannedlocation of the set of implants; a location of a set of implantssurgically to be placed in a patient; and an actual location of apatient as provided by a patient tracker attached to the patient,wherein a transform relates the patient tracker to the three-dimensionaldataset; b. using a tracking system to measure the location of the setof implants simultaneously with the patient tracker; and c.communicating a final location of the set of implants relative to thethree-dimensional dataset.
 2. The method of claim 1, wherein providingthe three-dimensional dataset includes obtaining the three-dimensionaldataset from a three-dimensional radiograph.
 3. The method of claim 2,wherein the three-dimensional radiograph is a cone beam computedtomogram.
 4. The method of claim 2, wherein the three-dimensionalradiograph is an intraoral scan.
 5. The method of claim 1, whereinproviding the three-dimensional dataset includes accessing digital filesrepresenting the three-dimensional dataset by a navigation system. 6.The method of claim 5, wherein using the tracking system includesregistering digital datasets representative of the planned location ofthe set of implants, the location of the set of implants, and the actuallocation of the patient are then registered to each other within acommon coordinate system.
 7. The method of claim 6, wherein registeringthe planned location of the set of implants, the location of the set ofimplants, and the actual location of the patient includes spatiallyaligning common features of each imagining modality using rigid-bodytransformation.
 8. The method of claim 1, further comprising determiningthe planned location of the set of implants.
 9. The method of claim 8,wherein determining the planned location of the set of implants includesoutlining anatomical features of the patient.
 10. The method of claim 9,wherein determining the planned location of the set of implants includesdetermining a desired position and a desired angulation of the set ofimplants.
 11. The method of claim 10, wherein determining the plannedlocation of the set of implants includes determining a hole size of forreceiving the set of implants.
 12. The method of claim 11, whereindetermining the hole size is calculated by using a formula defined asDo + 2 (Et + H x tan(Ea)).
 13. A method of dynamically tracking animplant procedure comprising: receiving by a tracking system a firstdigital data set representative of a three-dimensional radiographobtained of a patient; determining a planned implant location for adental implant based on the first digital dataset; attaching an implanttracking fiducial to the dental implant; attaching a patient trackingfiducial to the patient; positioning the tracking system relative to thepatient; and using the tracking system to measure a location of theimplant tracking fiducial simultaneously with a location of the patienttracking fiducial; and communicating the planned implant locationrelative to the location of the implant tracking fiducial.
 14. Themethod of claim 13, further comprising registering the implant trackingfiducial to the tracking system.
 15. The method of claim 13, wherein theimplant tracking fiducial includes a plate with a printed pattern. 16.The method of claim 13, further comprising forming holes in the dentalimplant.
 17. The method of claim 16, wherein forming holes in the dentalimplant includes determining a hole size by using a formula defined asDo + 2 (Et + H x tan(Ea)).
 18. The method of claim 13, furthercomprising projecting image coordinates of the planned implant locationinto the tracking system.
 19. The method of claim 13, further comprisingusing the planned implant location to cue the tracking system where tolook for the implant tracking fiducial.
 20. The method of claim 13,wherein the implant tracking fiducial is a shape of a protruding portionof the dental implant.